Functionalized polyacrylate esters, which are obtained by the transesterification of alkyl polyacrylate esters (alkyl groups with 1 to 4 carbon atoms) with special alcohols, which generally have functional groups, have recently been described repeatedly, for example, in the German patents 38 42 201 and 38 42 202, as well as in the German Offenlegungsschriften 39 06 702, 40 06 093, 41 23 478, 42 02 187 and 42 24 412. Compared to similar copolymers, these transesterification products have important advantages, such as, for example, a significantly more uniform molecular weight distribution. They are largely free of monomeric fractions. The synthesis of polyacrylate esters, the alcoholic ester component of which has olefinic double bonds, without the formation of higher molecular weight by-products, becomes possible by means of the transesterification method. For example, it is readily possible to transesterify polyacrylate esters with oleyl alcohol and, at the same time, with other compounds having hydroxyl groups.
Transesterification by these methods generally proceeds to the extent of up to about 70% and products with at least approximately random distribution of the alcohols, introduced by the transesterification along the polymer chain, are obtained.
These transesterification methods cannot be carried out without further ado with the corresponding alkyl polymethacrylate esters.
Admittedly, the reaction of polymethacrylate esters with a large excess of diethylaminoethanol at temperatures in excess of 150.degree. C. in the presence of titanates as catalysts is known from Chemical Abstracts 98 (No. 8, 54652f). Polymers are obtained here, a portion of the ester groups of which has been transesterified with diethylaminoethanol. At this temperature, however, relatively non-uniform products are obtained and thermal decomposition products cannot be avoided.
Surprisingly, however, it was found that, by adhering to certain structure parameters for the polymethacrylate esters that are to be reacted and to a suitable selection of process conditions during the transesterification, it is possible to transesterify one or both of the terminally linked ester groups. This enables novel polymethacrylate esters to be synthesized, the ester groups of which in the .alpha. and optionally in the .omega. position deviate from the ester groups in the chain.